Method of preparing dental fillings.



J. G. HOLLINGSWORTH. METHOD OF PREPARING DENTAL FILLINGS.

APPLICATION FILED IEB.21, 1914.

' 1,099,248. Patented June 9,1914

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UNITED STATES PATENT OFFICE.

JEIPTHA, G. HOLLINGSWORTH, OF KANSAS CITY, MISSOURI.

METHOD OF PREPARING DENTAL FILLINGS.

Application filed February 21, 1914.

To all whom it may concern:

Be it known that I, JEPTHA Gr. HoLLrNos- WORTH, a citizen of the United States, residing at Kansas City, in the county of J ackson and State of Missouri, have invented certain new and useful Improvements in Methods of Preparing Dental Fillings, of which the following is a specification.

This invention relates to an improved method of preparing dental fillings and my object is to devise a method whereby solid gold and enamel fillings may be prepared by cold process entirely outside the mouth of the patient and ready to be inserted into the cavity and secured in place by cement; thereby eliminating the pain and discomfort attendant upon condensing filling material directly into the cavity of a tooth. It is found that fillings prepared by this cold process are more desirable than those prepared by casting process, since the latter are I subject to temperature changes which do not insure a perfect fit .and oftentimes the character of the filling material is affected and rendered unsatisfactory.

The process herein described is particularly adapted for use in connection with the dental appliances forming the subject matter of my copending application No. 787356, filed Aug. 29, 1913.

With this general object in view, my invention resides in certain peculiar process steps as hereinafter explained and particularly pointed out in the appended claims, and to afford a clear understanding thereof, reference will be made to the accompanying drawing, in which.

Figure 1, is a broken perspective view illustrating the mode of taking a wax impression of the tooth cavity. Fig. 2, is a perspective view of the Wax after having taken the impression. Fig. 3, is a perspective View illustrating the application of the cement to the wax. Fig. 4, is a perspective view showing the manner of removing the wax from the matrix. Fig. 5, is a section showing the matrix mounted on a bed and ready to be packed with the filling material. Fig. 6, is a perspective view of the filling and matrix, the latter being broken preparatory to removing the filling.

Referring to the drawing, the cavity 2, of the tooth to be filled, is prepared as for an ordinary inlay filling, and in preparing the cavity care is taken not to undercut it at first. The cavity is then moistened and Specification of Letters Patent.

Patented June 9, 1914.

Serial No. 820,331.

with a sufficiently pliable piece of dental wax at, an impression 6, is taken of the cavity the taking of the impression beingfacilitated by pointing the piece of wax by finger pressure or otherwise, so that it may be inserted in the cavity more readily. To make the wax more facile it is warmed slightly and the impression made is of the marginal portion of the tooth as well as of the cavity. The impression is obtained in the same way as for east inlays. After the wax impression has been obtained as shown in Fig. 2,1 form a mold or matrix 8, cor-. responding to said impression by applying thereto a suitable mold or matrix forming material, such as quick setting cement, see Fig. 3. The cement is prepared sufficiently thin to flow over and into all parts of the impression, a fine brush being used to apply the cement, if necessary, and care beingexercised to prevent the formation of bubbles. After the cement has hardened, the wax is warmed until pliable and is then withdrawn from the cement form or matrix, care being exercised to allow no particles of the wax to adhere to the matrix. With the wax impression withdrawn there is left the cement matrix 8, with a cavity 10 representing an exact duplicate of the tooth cavity 2 to be filled. A cup 12 mounted removably on a convenient base or support 14, is then charged with a semi-liquid or plastic material having the property of quickly hardening to form a firm and solid bed 16, or such material may be employed to form a bed 16 independently of any cup or receptacle. \Vhile the bed 16 is soft, the cement matrix is bedded in it at any angle desired, and to insure the best anchorage, the dentist can work the bed material up around the edges of the matrix after the surplus portion of the same has been trimmed awayby putting a little of the powdered bed material on his fingers, using care to keep the surface margins of the matrix clear.

The operation of bedding the matrix is quickly performed and within a minute or two thereafter the bed 116 is hard and solid. As the cavity is the same shape as for east inlays, it will be necessary in a good many cases, especially where the bottoms of the cavities are round or flat, to cut a line or two in the matrix, 0. undercut as at 18, to prevent the filling 20, rocking while being condensed. The operator can now proceed to fill the cavity 12 with either cold gold or enamel as preferred, in the same manner as the same operation would be carried out in the mouth. Specifically the process is as follows:

In preparing a cold gold filling 20, mat gold is preferably employed, and in start ing to fill the matrix a piece of gold is placed on the bottom of the cavity, being forced in so that it shall enter the undercuts 18. Additional pieces of gold are then successively introduced into the cavity and condensed by any suitable plugging tool until the margins of the cavity are nearly reached. Then with a proper burnisher such as a tantalum burnisherand a plug ger, continue the condensing or packing operation in the same manner that one would pack amalgam, packing toward the mar gins, but using considerably more pressure than is necessary for condensing amalgam. After the cavity is full and the condensing operation finished, the inlay 18 is ground and finished the same as a gold filling in the mouth. The cement matrix is then broken away from they filling or inlay, and the latter is annealed to a red heatii formed with projections or fins from the use of undercuts, such projections or fins are removedthen cooled and placed in the tooth of the patient, any suitable inlay cement being used to secure it in place, it being understood that the cavity in the tooth can be undercut if, desired to guard against any possibility of loss through the loosening of the cement. In preparing fillings where little pressure is necessary to properly condense the filling materialsuch as used in enamel fillings, sealing wax first softened and then allowed to cool, has been found to provide a bed of suflicient'firnr ness. Ordinarily, however, sealing Wax is not dependable as it is liable to crack or check under the force necessarily applied in condensing cold mat gold into the matrix.

From the foregoing it will be apparent that I have devised a very simple, efficient and practical method for preparing fillings of the character described and while I have indicated what seems to be the essential steps comprising my improved method, I reserve the right to any minor departures therefrom, such as may fall within the spirit and scope of the appended claims.

I claim:

1. A method of preparing dental fillings, consisting in inserting a piece of moldable material such as wax into the tooth cavity to obtain an impression of said cavity, applying a quick setting material to said impression to form a mold, allowing said material to set in mold form, and then charging said mold with a filling material at a comparatively low temperature. 7

2. A method of preparingdental fillings, consisting in taking an impressionof the tooth cavity, forming a mold from said im pression, mounting said mold in a bed of cementiticus material and then charging said mold with. a cold filling material.

3. A method of preparing dental fillings, consisting in taking an impression of the tooth cavity, forming a mold fromsaid impression, embedding said mold in a base of cementitious material, charging said mold with a cold filling material and thenin annealing the molded filling.

In testimony whereof, I affix my signature, in the presence of two Witnesses.

JEPTHA Gr. HOLLJINGSIVORTH. Witnesses H. C. Rononns, G. Y. THORPE.

Copies of this patent may 'be obtained for five cents each, by addressing. the Commissioner of Patents,

Washington, D. C." 

